The Federal Reserve could issue its own digital currency, as some global central banks are exploring. Large companies such as Amazon, Walmart and Starbucks might issue digital coins that inspire trust and gain wide acceptance. Retail giants, by accepting payments in the currency, could elevate Bitcoin, Ethereum or another cryptocurrency above the others vying to offer safety, soundness and utility. Finally, if trust is lost in government-backed, or fiat, currencies, a cryptocurrency future could come about by default. That may be a risk not only in places like Venezuela, but in the U.S., where federal deficits are spiraling.